Only websites in the US will take stuff down. That's my experience. You can't get stuff off torrent sites. However you are not losing many sales because of this. Kids collect stuff off torrent sites but don't read them--they just collect them.

I have successfully terminated pirate sellers on two of the largest Chinese retail platforms. Many other sites do obey DMCA takedowns. Some don't.

BTW paper copies do not protect you. Basically everything is already available digitally. The best way to counter that is to have your own digital edition available. That way the majority will purchase from an honest retailer and not be tempted to download a pirated version.

Generally speaking, my experience is consistent with Richard's... China & Hong Kong are proving problematic. In at least one case, though, the moron behind the site didn't even bother masking his identity on whois. I invoiced him a few grand for licensing fees. Of course, this will go nowhere - but it's fun trying.

I wouldn't worry too much about it. The people stealing them most likely will never watch or read the material they stole. The same people will never pay for your product in the first place. It's unfortunate that it happens but their is very little legal recourse. Even 'legitimate' sites like scribd.com are flooded constantly with illegal uploads.